Manhole-cover.



UNITED Sra'rns ERNEST A. FALLER, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOROF TW O- TI-IIRDS TO OSCAR T. \VEBER AND HERMANN HERBSTRITT, OF SAMEPLACE.

MANHOLE-COVER.

SPECIFICATION forming part of Letters Patent No. 652,605, dated June 26,1900.

Applicaticu filerlDecember 21, 1899- Serial No. 741,181. (No model.)

To (LZZ whont it may concern:

Be it known that I, ERNEST A. FALLER, a citizen of Germany, residing atSan Francisco, in the county of San Francisco and State of California,have invented certain new and useful Improvements in hlanlloleCovers, ofwhich the following is a specification.

My invention relates to manholes for altord ing access to undergroundreceptacles, conduits, tunnels, &c., and to the covers for suchmanholes.

The object of my invention is to prevent water from entering the manholefrom above. I accomplish this object by a construction which forms adouble water seal, between which a body of air is confined.

In the accompanying drawings, Figure 1 is a plan view of the manholecasing and cover, with the latter partly broken away. Fig. 2 is anelevation of the casing, partly broken away to show the cover inposition. Fig. 3 is an enlarged vertical section through the jointbetween casing and cover, showing the upper and lower water seals andthe intermediate air-space.

A represents the manhole-casing, which is shown as circular in planview, but which may be of any desired shape. This casing is fitted atthe mouth of the manhole and there secured in place. The casing isformed with a rim or flange 1, which surrounds the seat 2, upon whichthe cover B rests. The top of the cover is flush with the upper edge ofthe rim 1, which may be assumed to be the ground or street level. Thecasing is further provided with two channels 3 and 4. I prefer to makethe channel 3 comparatively shallow, while the channel 4: is relativelydeep, as shown; but this is not essential, although desirable assimplifying the construction. These channels are separated by a wall 5,which is practically an upward continuation of the main wall of thecasing. This wall rises to nearly the level of the seat 2, leaving aspace below the cover, which is a communication between the channels.

The cover B is of such size and shape as to loosely fit the rim 1 and torest upon the seat 2 and is provided on the lower face with con tinuousflanges 6 and 7. When the cover is in place, these flanges enter thechannels 3 and 4, respectively, forming in each two spaces, as shown.The flanges are of about the same relative depths as the said channels.Each of the channels forms a receptacle for water, and the flangesdipping into such water form inner and outer air-tight seals.Necessarily the air confined in the space between the two bodies ofwater is compressed, raising the water in the inner space 8 of channelat to a certain height only, which is depend ent upon the height ofwater in the other seal plus any water standing outside-as in thestreet, for instance. It will thus be readily seen that while the outerchannel may be shallow the inner channel must be deep enough to give amargin of safety in case water should be standing in the street abovethe manhole. While there is no attempt made to produce a watertightjoint between the cover and casing and while a certain quantity of Watercan enter freely until the channel 3 is filled, the air compressedbetween the two bodies of water atfords a complete resistance to thefurther passage of water from channel 3 to channel 4. In the operationof the device, and assuming that both channels are dry, water can enterbetween the cover and easing until the channel 3 is filled. The watercan then flow over the top of wall 5 and into the inner channel, risingtherein until the water seal has been established and the escape of airin channel 4 cut off. As more water enters the joint at the ground-levelthe confined air is compressed and the water in the inner seal rises inspace S to such a height as will by its weight coun terbalance thecolumn of water in communication with the street. The equilibrium beingthus established, the entrance of more water is rendered impossible.

The advantages of my device as to simplicity and efficiency are apparentand need no de tailed recital. It is adapted to all situations in whichunsheltered manholes are used as means of communication with lowerreceptacles, tunnels, conduits, 8m.

Where it is desired to prevent the escape of gases from the manhole, theinner channel maybe primed with water in the first instance, but inothercases this is unnecessary, as has been demonstrated in practice.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is-

1. In combination, a manhole-casing having concentric channels and acover having concentric flanges or ribs depending therefrom of lessthickness than the width of the channels with water-passages between thebottoms of the flanges and channels, and between the bottoms of thecover and tops of the Walls of the flanges, substantially as described.

2. In combination, a manhole-casing having concentric channels and acover having flanges depending into said channels of less thickness thanthe width of the channels and means for holding said cover above thetops of the channels and with the bottoms of the flanges above thebottoms of the channels, substantially as described.

3. In combination, a manhole-casing having a platform or seat andinterior concentric channels, a cover having its edge supported uponsaid platform, and having concentric flanges depending into saidchannels, said flanges being of less thickness than the Width of thechannels, and water-passages between the bottoms of the flanges andbottoms of the channels and also between the tops of the channels andthe bottoms of the cover, substantially as described.

4:. The combination with a manhole-casing having a seat or platform anda surrounding rim,and inner concentric channels of increasing depth, ofa cover resting on said seat and having concentric flanges dependingwithin said channels and of less thickness than the Width of saidchannels, said flanges terminatin g above the bottoms of the channelsand the tops of the channels short of the bottom of the cover,substantially as described.

In testimony whereof I have aflixed my sig nature, in presence of twowitnesses, this 15th day of December, 1899.

ERNEST A. FALLER.

\Vitnesses:

L/W. SEELY, OSCAR T. WEBER.

